JP7046946B2 - Priority association between the slave unit and the master unit operating in the time slot channel hopping network - Google Patents

Description

The present disclosure relates generally to networks and specifically to a mechanism for a preferred association between a slave unit and a master unit operating in an IEEE 802.15.4 or IEEE 802.15.4e time slot channel hopping network.

A system and method for establishing a preferred association between a slave unit and a master unit operating in a time slot channel hopping (TSCH) network are provided. Utility companies, home automation providers, industrial automation providers, scientific and environmental application providers, and other resource providers are provided by TSCH networks such as IEEE802.5.4 and IEEE802.5.4 (e). It can communicate with endpoints via devices operating in a defined TSCH network. The master unit (for example, an electric meter, a router) is connected via the TSCH network. Here, the master unit is also referred to as a master node or a TSCH node. The slave unit is an endpoint node used to monitor and / or manage the usage of resources (eg, power, heat, water, other utilities, and other types of resources). In certain embodiments, the slave unit (also referred to herein as a "child node") may be a device that has the functionality of the Internet of Things (IoT), which is a smart power grid and Can be used for smart home technology. The slave unit is used as an endpoint of the TSCH network to read power usage and communicate messages about other resource information with the master unit. In another embodiment, the slave unit may be a mobile device, which passes through the coverage area of one or more master units in the TSCH network.

A master unit operating in the IEEE 802.15.4 network can support a limited number of slave units. Once the maximum number of slaves have been joined / associated (ie, associated) with the master, the master can no longer accept additional slaves. It is necessary to establish a priority association (association) between the master unit and the slave unit that joins the network and requests priority access to the TSCH network.

A system and method for establishing a preferred association between a master unit operating in a time slot channel hopping (TSCH) network and a slave unit are provided. The child node may run in a Home Area Network or other local network to provide resource monitoring services to the resource provider over the TSCH network. At initialization and rising, the child node scans for the parent node available in the TSCH network. Hardware and network characteristics and limitations, the parent node can support a limited number of child nodes at the same time. An available parent node is a parent node that has the capacity to support at least one additional child node. The child node determines whether to send a priority (right) association request based on the number of available parent nodes detected by the scan. If the child node determines that the number of available parent nodes is small (ie, less than the threshold number set by the network administrator), it inserts a preferred request into the association request. The priority request can be added by enabling the priority bit in the data packet sent for the association request. If the child node determines that the number of parent nodes is greater than the threshold number, the child node does not include the priority request.

The priority request may include a period request for priority for short-term or long-term priority. The short-term priority allows the slave unit to associate with the parent node for a sufficient period of time to complete the communication activity. For example, short-term priority allows a child node to associate with a parent node, send a resource usage / usage message to the parent node, and disassociate with the parent node when the transmission is complete. The child node may request a preferred association for a short period of time if it determines that the TSCH network is in the initialized state or the child node is about to run out of power. Long-term priority allows a child node to associate with a parent node for as long as the parent node is active. If the child node determines that the TSCH network is in the mature state, it may request a preferred association for a long period of time.

The TSCH parent node is configured to accept a preferred association request by holding one or more slots for a child node that has a preferred association request. The TSCH parent node keeps a record of a limited number of child nodes in its memory based on its hardware and network capabilities. The TSCH parent node reserves one or more entries for a child node requesting a preferred association request. In another embodiment, the TSCH parent node may choose to disconnect its association with one of its associated child nodes and accept preferred association requests from other child nodes. For example, it may decide to abort the association based on the minimum communicative radio and signal strength of the other child nodes. The TSCH parent node may maintain statistics and information about the connected child node (eg, whether the child node connected through a preferred association) with a child node that did not previously request a preferred association. You may choose to discontinue the association.

Although these exemplary embodiments and features are referred to as not limiting or defining the invention, illustrations are provided to aid in understanding the concept of the invention described herein. On the other hand, the advantages and features of the present invention become apparent when the entire application is examined.

A network diagram illustrating an exemplary arithmetic unit for a preferred association between a parent node and a child node operating in a Timeslot Channel Hopping (TSCH) network. Block diagram showing an example of a TSCH parent node Block diagram showing an example of a child node Time slot diagram showing the arrangement of time slots in the channel hopping pattern. A communication timing diagram representing a series of messages sent between a child node and a TSCH node to establish a preferred association. Flowchart showing an exemplary process performed on a child node to establish a preferred association with the TSCH parent node A flowchart showing an exemplary process performed on a TSCH parent node to establish a preferred association with a child node.

These as well as other features, embodiments and advantages of the present disclosure will be well understood by reading the following detailed description with reference to the accompanying drawings.

A system and method for establishing a preferred association between a slave unit and a master unit operating in a time slot channel hopping (TSCH) network are provided. The TSCH network includes, for example, a plurality of TSCH devices in a mesh network, the mesh network providing communication with a central system such as a resource provider system. The TSCH device communicates using the TSCH protocol defined by IEEE802.1.5.4. By communication utilizing the TSCH protocol, nodes in the TSCH network transmit and receive signals using a set of time slots based on a scheduled frequency channel hopping pattern. A parent node is a TSCH device that manages and supports one or more child nodes. For example, the child node may be an endpoint device located in the home area network and used to manage and / or monitor the consumption and usage of resources in the home area network. Therefore, the child node can report the resource usage to the resource provider via the TSCH network. In another embodiment, the child node may be a mobile device within the communication range of one or more parent nodes of the TSCH network, a device that needs to be temporarily connected to the TSCH network for short-term communication. There may be.

In certain embodiments, the child node may request preferred access to the parent node in the TSCH network. For example, in a particular embodiment, the child node may determine that it requires preferred access based on the number of available parent nodes it finds during its own network scan. Because a limited number of available parent nodes can indicate that the TSCH network is close to capacity limits and that child nodes can request preferred access to ensure establishment of communication with the TSCH network. Because. In other embodiments, the child node may be a mobile device that requires short-term priority access. In additional embodiments, the child node may be a low energy device (eg, a device powered by a battery power source or other energy source with limited energy capacity, such as a supercapacitor power source). A child node, which is a low energy device, may request priority access when its battery life is shortened.

Based on the specific characteristics described here, the child node may request preferred access to the parent node by including the priority request in the association request to the parent node within the communication range of the child node. .. The priority request is executed as a custom information element (IE) in the communication of IEEE 802.15.4 and IEEE 802.15.4e between the child node and the parent node. For example, the child node may contain a priority bit that is valid in the application layer data packet for the association request. Upon receiving a preferred association request, the parent node identifies a valid preferred bit and accepts or rejects the association request. If the parent node is already supporting the maximum number of child nodes, it may suspend the previously connected child node and temporarily accept the requesting child node's preferred association request for a short period of time. .. The parent node responds to the association request by sending an association response to the child node, whether it accepts or rejects the association request.

To increase the likelihood of accepting an association request, the parent node is configured to accept preferred associations. In particular, the parent node accepts a preferred association by deserving one or more slots of its maximum slot capacity for the child node requesting preferred access. For example, the parent node keeps a limited list of entries (based on maximum slot capacity) for connected child nodes in memory. One or more of the limited number of entries will be reserved for preferred connections. For example, a parent node may withhold five entries in the list of entries for a child node requesting preferred access if it is capable of supporting up to 50 child nodes. The number of slots reserved for child nodes requesting preferred access is configurable and can be programmed into the parent node during initial network establishment.

In certain embodiments, the priority request contained in the association request and sent to the child node may include a priority period request. For example, the period may be for short-term priority or long-term priority. In certain embodiments, the child node determines whether it contains a period request for short-term or long-term priority based on whether the number of parent nodes identified by the network scan has changed over time. For example, if the number of available parent nodes identified as being within range of a child node increases between one network scan and the next, it means that the TSCH network is still in the initialized state. Yes, it can represent that available parent nodes can be added as the network matures. If the child node determines that the network is still being initialized, it requests priority access with a short-term priority period request. If the number of available parent nodes identified as being within range of a child node remains the same after multiple network scans over a period of time, this may indicate that the network has matured. If the child node determines that the TSCH network is mature and the number of parent nodes identified within the communication range of the child node remains less than the threshold number of the parent node, the child node has a preferred access with a long-term priority period request. To request.

These illustrations are intended to introduce the reader to the general protections described herein and are not intended to limit the scope of the disclosed concepts. The following paragraphs illustrate various additional embodiments and examples with reference to the drawings, where similar numbers refer to similar elements.

Referring to the drawings, FIG. 1 is a network diagram showing an exemplary TSCH network 100 including TSCH nodes 102a to 102d, and the TSCH nodes 102a to 102d are communication-connected with the resource provider 110. The TSCH network 100 provides communication between the child nodes 104a-104d and the resource provider 110 via the network 115. For example, the network 115 may include any suitable network or intermediary calculator, including a private intranet or the Internet. Each of the TSCH nodes 102a to 102d may be a parent node of one or more child nodes 104a to 104d. For example, TSCH nodes 102b-102d are shown as exemplary parent nodes for child nodes 104a-104d. The parent TSCH devices 102c, 102d may include adjacent TSCH devices (eg, TSCH devices 102b, 102c adjacent to the TSCH device 102d, and TSCH devices 102b adjacent to the TSCH device 102c, via one or more wireless transmitters and receivers. It is also possible to communicate with 102d) and the connected child nodes 104a to 104c.

The child nodes 104a-104d may be used to execute one or more applications, which manage information about one or more attributes of the distribution system associated with the resource provider 110. Regarding monitoring or use. Non-limiting examples of such child nodes 104a-104d are intelligent metering devices for power usage monitoring and analysis, programmable thermostats for power usage management, power usage information and power. Includes a home display device for displaying related billing information for usage. The child nodes 104a-104d may be arranged as intelligent weighing devices in the home area network. Child nodes 104a-104d also include other devices with Internet of Things capabilities to provide smart home capabilities in home area networks. In certain embodiments, the child nodes 104a-104d also include a mobile device that traverses the radio range of one or more TSCH devices 102a-102d in the TSCH network 100.

The child nodes 104a-104d may be powered by an A / C power source or, in certain embodiments, may be powered by a limited power source. For example, the child nodes 104a-104d are powered by batteries or by supercapacitors. When the child nodes 104a-104d are run as devices powered by a limited power source, they are called low energy devices, periodically powering off components (eg, transmitters or transmitters / receivers), and sleeping. Save battery life by circulating between states and wake states. The child nodes 104a-104d may also operate in any suitable wireless network to communicate with each other and with the TSCH network 100 via the TSCH nodes 102c, 102d. In another embodiment, the child node may be a TSCH node requesting access to join the TSCH network (eg, a device operating according to the TSCH protocol). In other specific embodiments, the parent and child nodes may operate in a non-TSCH network, eg, a Carrier Sense Multiple Access (CSMA) network based on IEEE802.5.4.

The child nodes 104a-104d initiate the synchronization process associated with the TSCH network 100 by scanning the TSCH nodes 102a-102d available within the radio range when initializing or waking up from sleep. do. In the example shown in FIG. 1, the child node 104a is within the wireless communication range 110a of both the TSCH node 102b and the TSCH node 102d, while the child node 104b and the child node 104c are located only within the wireless communication range 110b of the TSCH node 102d. be. In a particular embodiment, the child nodes 104a-104d determine whether to send a preferred association request over the association process with the TSCH network 100. Based on the maximum available bandwidth, memory size, and hardware capabilities of TSCH nodes 102a-102d, TSCH nodes 102a-102d can simultaneously support a limited number of child nodes. Thus, the number of available TSCH nodes 102 decreases over time as the TSCH network 100 matures and the number of child nodes 104 associated with the TSCH node 102 increases. A child node 104 requesting an association with the TSCH network 100, a parent node if a limited number of available TSCH nodes 102 (eg, available TSCH nodes 102 less than the threshold number) are detected by the child node 104. You may request a priority association with.

For illustration purposes, suppose the TSCH nodes 102b, 102d have the maximum child node slot capacity of the two child slots. Further, the child nodes 104b and 104c were associated with the TSCH node 102d and joined the TSCH node 102d at the time before the initialization of the child node 104a. When the child node 104a initializes and initiates a network-related process, it scans for available parent nodes by patrolling the frequency channels used by the TSCH network 100 and listening to communications from the TSCH device. .. Even if the TSCH node 102d is within the communication range of the child node 104a, the node 104a identifies only the TSCH node 102b as an available parent node because the TSCH node 102d already supports the maximum number of child nodes. The child node 104a determines the number of available TSCH nodes 102, and the number of available TSCH nodes 102 (one available TSCH node 102b in this embodiment) is greater than the number of available parent node thresholds. Further judge that it is small. The number of available parent node thresholds that trigger a preferred association request from the child node 104 may be a configurable value that is programmed into the child node 104 and changed at run time prior to initialization.

FIG. 2 is a block diagram illustrating an example of the TSCH node 102d, which has a single transmitter / receiver 220 for communicating with adjacent TSCH nodes 102b, 102c and also connected child nodes 104b, 104c. .. The TSCH node 102d includes a processor 202. Non-limiting examples of the processor 202 are microprocessors, application-specific integrated circuits (ASICs), state machines, field programmable gate arrays (FPGAs), or other suitable processing. Includes equipment. Processor 202 may include any number of processors, including one. The processor 202 may be communicatively linked to a non-temporary computer-readable medium such as the memory device 204. The processor 202 may execute a computer-executable program command and / or may access the information stored in the memory device 204.

The memory device 204 may store a command, and when the command is executed by the processor 202, causes the processor 202 to perform the operation described here. The memory device 204 is a computer-readable medium, such as, but not limited to, an electronic, optical, magnetic, or other storage device capable of providing computer-readable commands to the processor. Non-limiting examples of such optical, magnetic, or other storage devices are read-only devices, ROM devices, random-access memory (RAM) devices, and magnetic disks. Includes, magnetic tapes or other magnetic storage devices, memory chips, ASICs, configured processors, optical storage devices, or other media from which computer processors can read commands. The directives may include processor-specific directives generated by the compiler and / or interpreter from code written in any suitable computer programming language. Non-limiting examples of suitable computer programming languages are C, C ++, C #®, Visual Basic®, Java®, Python®, Perl, Javascript®. , ActionScript® and the like.

The TSCH node 102d may also include a bus 206. The bus 206 may communicate-link one or more components of the TSCH node 102. In FIG. 2, the processor 202, the memory device 204, and the bus 206 are each shown as separate components communicating with each other, but other embodiments may be possible. For example, the processor 202, the memory device 204 and the bus 206 are other suitable devices located on the TSCH node 102d to store and execute the respective components of each printing circuit board, or the programmed code. May be good.

The TSCH node 102d may also include a transmission / reception device 220 communication-connected to the processor 202 and the memory device 204 via the bus 206. Non-limiting examples of transmitter / receiver 220 include RF transceivers or other transmitters / receivers for transmitting and receiving signals wirelessly. The transmitter / receiver 220 is used by the TSCH node 102 to communicate with the adjacent TSCH nodes 102b, 102c and the connected child nodes 104a, 104b via the antenna 208. In a particular embodiment, the transmitter / receiver 220 has the ability to perform a plurality of MAC interfaces with a plurality of antennas and communicate with adjacent TSCH nodes 102b, 102c and connected child nodes 104a, 104b. The TSCH node 102d may communicate with adjacent TSCH nodes 102b, 102c and connected child nodes 104a, 104b via the same network protocol or different network protocols using a single transmitter / receiver 220. For example, the TSCH node 102d may communicate with the child node 104 when powered by a battery, may be configured to operate using the low energy TSCH protocol, and in the low energy TSCH protocol the child. Node 104 switches frequency channels relatively slowly compared to the channel hopping pattern used in the TSCH network. The TSCH node 102d may communicate with the child nodes 104a and 104b connected to the adjacent TSCH nodes 102b and 102c even when the TSCH node 102 and the child node 104 use different frequencies. In another embodiment, the child node and the TSCH node may communicate at the same frequency.

Although the TSCH node 102d is shown to have a single transmitter / receiver 220 for illustrative purposes, in certain embodiments, the TSCH node 102d may include multiple transmitters / receivers. For example, in an embodiment in which the TSCH network 100 operates with a different frequency set or modulation technique from the connected child nodes 104a, 104b, the TSCH node 102 may include a plurality of transmit / receive devices to communicate using different modulation techniques. For example, a first transmit / receive device (configured for a first frequency set or modulation technique) may be utilized for communication with adjacent TSCH nodes 102b, 102c (second frequency set or modulation technique). The second transmitter / receiver (configured for) may be utilized for communication with the nodes 104b, 104c.

FIG. 3 is a block diagram illustrating an example of a child node 104c for communicating with the parent node 102d. The child node 104 includes a processor 302 fully interconnected via the bus 306, a memory 304, and a transmitter / receiver 320. The processor 302, the memory 304, the transmission / reception device 320, and the bus 306 perform the same operations as described with respect to FIG. In the embodiment in which the child node 104c is powered by a battery, the processor 302, the memory 304, the transmitter / receiver 320, and the bus 306 are powered by a battery (not shown).

As described above, the TSCH network 100 wirelessly communicates information inside and outside the network using the TSCH protocol. In the TSCH network, the devices in the network are synchronized based on the TSCH channel hopping pattern. In an embodiment in which the TSCH nodes 102a to 102d and the child nodes 104a to 104d operate by different networks or protocols, the TSCH nodes 102a to 102d communicate with the TSCH network and the child nodes 104a by subdividing the TSCH time slot. The communication period with ~ 104d may be alternately performed. An exemplary technique for alternating the communication period with the main TSCH network 100 and the communication period with the networks used for the child nodes 104a-104d by subdividing the TSCH time slot is titled "Resource Provider". And Interleaved Communication with Home Area Networks, US Patent Application No. 14/830271, the contents of which are incorporated herein by reference.

In the TSCH network 100, each time slot is for a time period "T" that can be defined by milliseconds or other suitable time unit. The TSCH network also utilizes multiple channel frequencies for communication with different devices in the network. The hopping pattern defines the channel used for communication over each time slot. FIG. 4 is a diagram showing time slots and channel hopping patterns for a TSCH network according to the TSCH protocol. FIG. 4 shows time slots 411 to 415, 421 to 425, and 431 to 436, each having the same time slot period 430. As an example, the time slot period may be 25 milliseconds. Each of the slot frame 410 and the slot frame 420 contains seven time slots. FIG. 4 also shows a channel hopping pattern 440 (shown as channel hopping patterns 440a-440c). The channel hopping pattern defines a channel frequency or channel for each time slot in the hopping pattern. For example, the hopping pattern 440a may be channel 4, channel 6, channel 3, channel 5, channel 7, that is, channel 4 is associated with time slot 1, channel 6 is associated with time slot 2, and channel 3 is associated. The channel 5 may be associated with the time slot 3, the channel 5 may be associated with the time slot 4, and the channel 7 may be associated with the time slot 5. In FIG. 4, the hopping pattern 440a has a hopping pattern length of 5. The hopping pattern is repeated. An exemplary iteration hopping pattern 440a has time slots 1-5 (411-415) and a second iteration hopping pattern 440b has time slots 6-10 (411-415). The hopping pattern 440c of the third iteration has time slots 11-15 (431-435). The number of time slots in the hopping pattern may be independent of the number of time slots in the slot frame.

FIG. 5 shows a communication timing diagram between the child node 104a and the TSCH node 102b of the TSCH network 100 to establish a priority association. The communication timing in FIG. 5 is intended to indicate a series of messages transmitted between the child node 104a and the TSCH node 102b when establishing a preferred association.

When it is determined that the association request should include the priority request in order to associate with the TSCH network 100, the child node 104a sends the priority association request to the TSCH node 102b over the first time period 510. Accordingly, the TSCH node 102b sends an acknowledgment message to the child node over a second time period of 520. The child node 104a may send a preferred association request if it has not received an acknowledgment message over the threshold time period. As further described below with respect to FIG. 7, the TSCH node 102b determines whether to accept or reject the preferred association request and sends a preferred association response 530 to the child node 104a over a third time period of 530. The preferred association response indicates whether the TSCH node 102b has accepted or rejected the association request.

It should be noted that although acknowledgment messages and preferred association responses from TSCH node 102b are shown to be transmitted as separate communications over a second time period 520 and a third time period 530, respectively. In certain embodiments, the preferred association response and acknowledgment messages may be combined into a single message and sent to the child node 104a.

Upon receiving the preferred association response, the child node 104a sends an acknowledgment message to the TSCH node 102b over a fourth time period of 540. The TSCH node 102b may retransmit the preferred association response if it has not received the acknowledgment message over the threshold time period. After that, when the TSCH node 102b accepts the association request, the child node 104a and the TSCH node 102b start the association and perform the procedure specified by IEEE 802.15.4 or IEEE 802.15.4e.

FIG. 6 is a flow chart illustrating an exemplary method 600 performed by child node 104a to initiate a preferred association request such as connecting to TSCH node 102b. For exemplary purposes, Method 600 will be described with reference to embodiments of the system shown in FIGS. 1-3, with reference to the illustration of the TSCH time slot shown in FIG. However, other embodiments are also possible.

As shown in block 610, process 600 involves scanning one or more available parent nodes in the TSCH network. For example, when initialization begins or when waking up from sleep, the child node 104a scans the TSCH parent nodes 102b, 102d available within its communication range. The scan is performed by patrolling different frequency channels used in the TSCH network 100 and listening to communications from adjacent TSCH parent devices 102b, 102d. The TSCH parent device intermittently broadcasts a beacon signal indicating availability. The beacon signal may include information indicating whether the TSCH parent device accepts a new child node. The child node 104a can determine that the TSCH parent nodes 102b, 102 are available by listening to the beacon signal.

The child node may determine if preferential access to the parent node is required based on the number of available TSCH parent nodes 102b, 102d found by scanning. For example, if the child node identifies a threshold number of available TSCH parent nodes within its communication range, it determines that preferential access is not required. When the child node identifies an available parent node within the communication range that is less than the threshold number, it determines that priority access is required.

In a particular embodiment, the child node 104a identifies the number of TSCH parent nodes 102b, 102d within the communication range, and the number of identified TSCH parent nodes 102b, 102d, regardless of the availability of the parent device. Determine if a preferred association request is requested based on. For example, the child node 104a scans the adjacent TSCH parent nodes 102b, 102d by scanning or by communication from adjacent TSCH devices 102a-102d, circling around different frequency channels used in the TSCH network 100. In this example, the child node 104a does not determine if the identified parent devices 102a-102d are available, but identifies adjacent parent devices 102b, 102d. When the number of the parent devices 102b and 102d identified within the communication range is less than the threshold number, the child node 104a determines whether to transmit the priority request.

As shown in block 620, when it is determined that the number of TSCH parent devices 102b, 102d is less than the threshold number within the communication range of the child node 104a, the first of the one or more parent nodes 102b, 102d. The child node sends a preferred association request to the parent node 102b of. For example, when it is determined that the number of TSCH parent devices 102b, 102d is less than the threshold number, the child node 104a may include the priority request in the form of valid bits in the data frame on which the association request is placed. The number of thresholds for determining whether a priority request is included may be programmed into the child node 104a prior to network deployment and set when the child node 104a is placed.

In certain embodiments, the association request comprises a period request for short-term or long-term priority. The short-term priority request refers to the priority required for a limited time period (eg, the time period required to complete a single communication activity between the TSCH node 102b and the child node 104a). .. For example, a short-term priority request allows the child node 104b to be associated with the TSCH node 102a for a particular activity or task, such as reporting a power current usage meter to the TSCH node 102b. After the data communication is completed, the child node 104a cancels the association from the TSCH node 102b. The long-term priority request refers to a priority that is associated long until the child node 104a requests the discontinuation of the association from the TSCH node 102b as long as the TSCH node 102b is active and powered.

The child node 104a determines whether it includes a short term period request or a long term term request together with a preferred association request based on one or more conditions in the TSCH network 100 detected by the child node 104a. For example, the child node 104a may determine whether it contains a short term or long term request based on whether the child node 104a determines that the TSCH network 100 is in the initialized or mature state. ..

With the TSCH network 100 in the initialized state, the TSCH network 100 is still initialized, and the TSCH nodes 102a to 102d are activated, connected to and synchronized with the adjacent TSCH devices 102a to 102d, and listened to. It refers to broadcasting a beacon transmission notifying the availability to the child nodes 104a to 104d. The child node 104a may determine that the TSCH network 100 is in the initialized state by comparing the number of acquireable TSCH nodes 102a to 102d detected as being within the communication range over the threshold time period. For example, when the child node 104a determines that the number of TSCH nodes 102a to 102d that can be acquired through a plurality of network scans has increased over a threshold time period, the TSCH nodes 102a to 102d are activated and become the TSCH network 100. Since the process of synchronization is being performed, it is determined that the TSCH network 100 is still in the initialized state. When it is determined that the TSCH network 100 is in the initialized state (and when it is determined that the number of TSCH nodes 102b, 102d that can be acquired is smaller than the threshold number as described with respect to the block 620), the child node 104a Includes priority association requests with period requests for short-term priorities.

The mature TSCH network 100 means that the TSCH network 100 contains a stable number of active TSCH nodes 102a-102d over a threshold time period (threshold time period values are programmed for child nodes 104). It can be adjusted by). For example, if it is determined that the number of TSCH nodes 102b, 102d that can be acquired through multiple network scans is maintained at a constant for a threshold time period, the new TSCH nodes 102b, 102d are no longer detected. , The child node 104a determines that the TSCH network 100 is in a mature state. When it is determined that the TSCH network 100 is in a mature state (and when it is determined that the number of TSCH nodes 102b, 102d that can be acquired is smaller than the threshold number as described with respect to block 620), the child node 104a is long-term. Includes a preferred association request with a period request for priority.

Other conditions may also cause the child node 104a to send a period request for short-term priority. For example, in certain embodiments, the child node 104a may include a mobile device within the range of one or more TSCH nodes 102a-102d of the TSCH network 100. In such an example, the mobile device may require short-term access to the TSCH node 102b within the communication range, whereby the TSCH node 102b routes communication from the mobile device to the external network. The mobile device may include a period request for short-term priority when it determines that a priority association request is necessary. In another embodiment, the child node 104a may operate on battery power and transmit a period request for short-term priority when the battery level is low. In another embodiment, the child node 104a may transmit a period request for short-term priority when informed that there is application data to be transmitted.

In certain embodiments, the child node 104a may send an association request with a short term request that does not require priority. For example, when it is determined by the network scan that the TSCH node parents 102b and 102d within the communication range of the child node 104a are less than the threshold number, the child node 104a may send an association request for short-term priority having no priority. good. In one example, when the child node 104a needs to join any parent node 102b, 102d but does not require an association with a particular parent node, it makes an association request for short-term priority with no priority. You may send it. If the child node 104a needs to connect to a specific parent node 102b, 102d, it may send an association request for short-term priority with priority.

As shown in block 630, process 600 further comprises receiving an association response from the parent node 102b that accepts or rejects the association request. The association response that accepts the association request means that the TSCH node parent 102b has added the child node 104a to the connection list of that node. Upon receiving the association response to accept the request, the child node 104a and the TSCH node parent 102b initiate a synchronization process to synchronize the child node 104a with the TSCH network 100. When the child node 104a receives the association response that rejects / rejects the association request, the child node 104a transmits the priority association request to the next acquireable TSCH node 102d within the communication range.

If the child node 104a has already requested short-term priority from the parent node 102b, as described for block 620, when communication with the parent node 102b is complete (eg, the power usage of the monitored home area network). Disconnect / abort the association from the parent node 102b (after completion of sending or receiving communication messages related to activities such as reporting).

FIG. 7 is a flow chart illustrating an exemplary process 700 executed by a parent node 102d to receive and process an association request from a child node 104b, which parent node 102b has the ability to support a preferred association request. .. For exemplary purposes, Method 700 will be described with reference to the embodiments of the system shown in FIGS. 1-3, with reference to the illustration of the TSCH time slot shown in FIG. However, other embodiments are also possible.

As shown in block 710, the process 700 includes receiving an association request from the child node 104b at the TSCH parent node 102d operating on the TSCH network 100. The TSCH parent node 102d maintains a list of entries for the connected child node in its memory 204. The number of entries is a limited number based on the maximum slot capacity for the TSCH parent node 102d (ie, the maximum number of child nodes that the parent node 102d can support at the same time). To accept the preferred association request, the TSCH parent node 102d reserves at least one entry out of a limited number of entries for the preferred association request from the child nodes 104a-104d. Thus, the first set of entries out of a limited number of entries is utilized by the TSCH node 102d for association requests that are received and have or do not have a preferred request. A second set of entries out of a limited number of entries is reserved by TSCH node 102d for an association request that has been received and has a preferred request. When the child nodes 104b, 104c associate and join the TSCH node 102d, the TSCH node 102d stores each of the associated child nodes 104b, 104c in the list of entries until it supports the maximum child node 102d. .. In certain other embodiments, the TSCH node 102d does not have to withhold an entry due to a priority request. In this case, when the TSCH node 102d receives the priority request, it reduces one already connected child node based on one or more parameters (eg, the time of the last received packet, the lowest signal strength, etc.). You may choose that.

The recording in memory 204 may be performed as any suitable software table or database to store information in the list of connected child nodes. For example, the recording is an identifier (eg, an IP address or MAC address) for the child nodes 104b, 104c supported by the TSCH node 102, if the child nodes 104b, 104c have requested or requested a preferred association. May include information such as the duration of the priority request.

As shown in block 720, process 700 further includes determining whether the association request includes a priority request. For example, the TSCH parent node 102d processes an incoming association request packet and identifies a valid priority bit, which indicates that the child node 104b has requested a priority association.

As shown in block 730, if the association request does not include a preferred request, the TSCH node 102d determines if an unpending entry is available in the list of a limited number of entries. Retrievable non-pending entry means that the TSCH node 102d has the ability to assist additional child nodes that do not have a priority request. As shown in block 750, the TSCH node 102d has no unreserved entries available (ie, on child nodes 104b, 104c to which all of the non-pending entries in the list of a limited number of entries are connected. If it is determined that it is full), the association request is rejected. As shown in block 740, the TSCH node 102d accepts an association request if it determines that it is not reserved for a preferred association request and that there is at least one retrievable entry. The TSCH node 102d further adds information about the child node 104b that sent the association request to this retrievable entry.

As shown in block 750, if the association request contains a preferred request, the TSCH node 102d is a non-pending entry or a pending entry (ie, an entry pending for child nodes 104a-104d having a preferred association request). Determines if is available from a limited list of entries. If there is an entry that can be obtained, the TSCH node 102d accepts the preferred association request and adds the information of the child node 104b requesting the preferred association to the list of entries of the connected child node. In certain embodiments, the TSCH node 102d accepts a preferred association request for a long-term association (as long as the TSCH node 102d is active). In certain situations, the TSCH node 102d may have multiple retrievable connection slots (ie, multiple non-pending entries may be retrievable in the list of entries). In these embodiments, if the preferred association request from the child node 104b includes a period request for long-term priority, the TSCH node 102d contains information about the child node 104b in the non-pending entry. If the preferred association request from the child node 104b includes a period request for short-term priority, the TSCH node 102d contains information about the child node 104b in the pending entry of the pending child list. However, other embodiments are also possible.

As shown in block 760, if there are no retrievable entries, i.e. that the TSCH node 102d is supporting the maximum number of child nodes 104b, 104c, the TSCH node 102d sends a preferred association request. Continues to associate with the child node that was previously connected, but aborts the previously connected child node without priority until the threshold number of priority associations is achieved. The number of thresholds can be set by the network administrator via the setting of the TSCH node 102d. When associated with a threshold number of preferred child nodes, the TSCH node 102d rejects subsequent association requests from additional child nodes.

For example, referring to FIG. 1, the child node 104b may be a previously connected child node already associated with the TSCH node 102d. When the TSCH node 102d receives an association request having a priority request from the child node 104c, the TSCH node 102d may reject the association request, and temporarily associates with the child node 104b in order to allow a short-term association of the child node 104c. You may cancel it. The TSCH node 102d temporarily removes the child node 104b from the list of pending entries and makes the child node 104c a pending entry for a short period of time (eg, a time period during which the child node 104c completes a single communication activity). Add to list.

In a specific embodiment, the TSCH node 102d may change the priority period setting of the connected child nodes 104b, 104c based on the network conditions. For example, in certain situations, the first connected child node 104b (connected through a preferred association with long-term requirements) may leave the range and stop communicating with the TSCH node over the time threshold. .. In such an embodiment, when the second connected child node 104c tries to associate with the TSCH node 102d by using the priority association, the TSCH node 102d changes the priority period setting of the first connected child node 104b. You may. The time threshold can be set by the network administrator.

The process 700 further includes transmitting the association response from the TSCH node 102d to the child nodes 104b and 104c that requested the association. The association response indicates that the association request from the child node has been accepted, or has been rejected / rejected with information indicating the reason for the rejection (for example, the network has reached the capacity limit).

The subject of protection has been described in detail herein in connection with the specific concepts of implementation, but those skilled in the art will appreciate the above description to provide alternatives, variations or equivalents of such embodiments. It will be appreciated that the example can be easily manufactured. Therefore, it should be understood that this disclosure is disclosed for purposes of illustration rather than limitation, and to those of skill in the art, the inclusion of modifications, modifications and / or additions to this protection is apparent. Not excluded.

Claims (16)

A method (600) performed by a child node (104a), wherein the child node (104a) is an association request to connect with a parent node (102b) operating in a time slot channel hopping (TSCH) network (100). To start,
Method (600) is
Scanning (610) with one or more available parent nodes (102b, 102d) in the TSCH network (100) by the child node (104a).
When it is determined that the number of available parent nodes (102b) is less than the threshold number within the communication range of the child node (104a), the one or more available parent nodes (102b, 102d) The association request is sent to the first parent node (102b), and the association request includes the priority request (620).
Receiving an association response from the first parent node (102b) that accepts or rejects the association request (630).
The method (600). The method (600) of claim 1, wherein the association request comprises a period request for short-term or long-term priority. The child node (104a) determines that the TSCH network (100) is in the initialized state based on determining whether the number of the parent nodes (102b, 102d) that can be acquired has increased over the threshold time period. The method (600) of claim 2, wherein the association request, when made, comprises the period request for short-term priority. It is determined by the child node (104a) that the TSCH network (100) is in a mature state based on determining whether the acquireable number of the parent nodes (102b, 102d) has changed over a threshold time period. The method (600) of claim 2, wherein the association request comprises the period request for long-term priority. The association response received by the child node rejects the association request.
The method is (600),
The first aspect of claim 1, wherein the association request is transmitted to the second parent node of the one or more available parent nodes (102b, 102d), further comprising the association request including the priority request. Method (600). Processing device (202) and
A child node (104a-104d) with a non-temporary computer-readable medium (204).
The processing device (202) is
Scanning one or more available parent nodes (102a-102d) in the Timeslot Channel Hopping (TSCH) network (100) by the child nodes (104a-104d).
When it is determined that the number of available parent nodes (102a to 102d) is less than the threshold number within the communication range (110a, 110b) of the child nodes (104a to 104d), the one or more can be used. The association request is transmitted to the first parent node (102b) among the parent nodes (102a to 102d), and the association request includes the priority request.
Receiving an association response that accepts or rejects the association request from the first parent node (102b).
Child nodes (104a-104d) configured to execute a command implemented on the non-temporary computer-readable medium (204) to perform an operation comprising. The child nodes (104a-104d) are mobile devices that are temporarily within the communication range of the one or more parent nodes (102d) of the TSCH network (100), and the association request is for short-term priority. The child node (104a-104d) according to claim 6, which includes a period request. The child nodes (104a to 104d) determine whether or not the remaining battery level of the child nodes (104a to 104d) is low, and when the remaining battery level of the child nodes (104a to 104d) is low, the child node (104a to 104d) has a low battery level. 104a-104d) The child node (104a-104d) of claim 6 or 7, wherein the association request is configured to include a period request for short-term priority when determined by 104a-104d). The parent node (102d) operating in the time slot channel hopping (TSCH) network (100) receives an association request for communicating with the parent node (102d) from the requesting child node (104b) (710). The association request contains a priority request, and the parent node keeps a list of a limited number of entries for the child nodes (104a-104d) to which the parent node (102d) is connected in its memory. (102d) withholds, receives (710) at least one entry out of a limited number of entries for a preferred connection, and
When the parent node (102d) determines that the association request contains the priority request, the list of the limited number of entries for the connected child nodes (104a-104d) is maximized. Accepting an association request for a short-term or long-term association based on the number (740), the identifier identifying the requesting child node (104b) is the limited number of identifiers for the preferred connection. By adding to the at least one entry of the entries, the association request is accepted, accepted (740), and
Sending (770) an association response indicating which said association request was accepted or rejected to the requesting child node (104b).
Equipped with
The method (700), wherein the received association request corresponds to an association request transmitted from the child node when it is determined that the number of available parent nodes within the communication range of the child node is less than the threshold number . The parent node (102d) is one of a plurality of TSCH nodes that provide communication between a utility resource provider and a plurality of child nodes (104a-104d) located in one or more home area networks. The method (700) according to claim 9, wherein the requesting child node (104b) is one of the plurality of child nodes (104a to 104d). Determining that the limited number of entries for the connected child node has been maximized (730), and
Suspending the association of a previously connected child node (104c) (760), the priority request from the requesting child node (104b) is accepted for a short-term or long-term association. Pausing (760) and
The method (700) according to claim 9 or 10, further comprising. The short-term association is any of claims 9-11, for the time period required to complete the communication activity between the requesting child node (104b) and the parent node (102d). The method according to paragraph 1 (700). When the communication activity is completed, the association with the requested child node (104a to 104d) is stopped.
12. The method (700) according to claim 12 . Determining that the limited number of entries for the connected child node (104a-104d) has not been maximized (750) and from the requesting child node (104a-104d). The association request is accepted for the long-term association (740), determining (750),.
The method (700) according to any one of claims 9 to 13, further comprising. A parent node (102d) that operates in a time slot channel hopping (TSCH) network (100) and is applied to perform the method of any one of claims 9-14. 15. The parent node (102d) of claim 15, comprising a routing device for providing communication between the child node (104b) and the utility resource provider.

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